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Senior Team


Photo of Michael Zimmerman

Michael Zimmerman, Chief Executive Officer

     In December 2023, Michael stepped into leadership, bringing over three decades of comprehensive experience in healthcare administration. His career, rooted in Long Term Care over 35 years ago, evolved through significant roles, including a five-year stint as a healthcare consultant and a transformative period as a hospital CEO. Michael's expertise spans managing hospitals of various sizes in states like California, Arizona, New Mexico, and Texas, where he adeptly navigated financial, governance, and regulatory challenges, often bridging the gap between administrative functions and clinical care.

     Michael's approach to leadership is informed not just by his professional journey but also by his personal life. Married to a Nursing Educator and a father to two successful adults and a grandfather, he values the human side of healthcare deeply. His family life, enriched by the presence of big dogs and a close-knit family, complements his professional vision, making him a well-rounded leader poised to steer healthcare organizations towards success with empathy and strategic insight.



Photo of Diahann Barrera

Diahann Barrera, Chief Financial Officer

     Diahann brings over 30 years of experience and expertise in finance, operations management, and administration within both for-profit and non-profit organizations, significantly contributing to the healthcare industry. Her journey began in dental healthcare before expanding into the medical field in 1994, underscoring her versatility and commitment to healthcare advancement. After earning her Master of Business Administration, Diahann ascended to the role of Vice President of Finance and Operations for a Community Health Center in 2002, where she demonstrated her proficiency in managing complex budgets up to $120M.

     In March 2024, Diahann took a significant step by joining John C Fremont, bringing her wealth of knowledge and strategic vision to the institution. Her engagement doesn't stop at professional achievements; Diahann is deeply involved in her community, reflecting a leadership style that is both impactful and grounded in a genuine desire to contribute to societal well-being.



Photo of Thomas Wilkinson

Thomas Wilkinson, Chief Nursing Officer

     Thomas brings a rich and diverse background to the JCF leadership team. Starting in the propane industry in Vermont, Tom transitioned to healthcare, demonstrating exceptional dedication and skill. As a valedictorian of his nursing class, he has extensive experience in emergency and critical care nursing, highlighted by his work in Emergency Rooms and as a Critical Care Transport RN. After moving to California in 2013, Tom's leadership abilities flourished, leading to roles such as RN house supervisor and ER charge nurse, culminating in his tenure as Chief Nursing Officer

     With board certifications in Emergency Nursing (CEN) and Critical Care Nursing (CCRN), and a Master of Nursing (MSN) from Capella University in Leadership/Administration and Education, Tom is not only a committed healthcare professional but also a passionate musician. He is eager to leverage his expertise and enthusiasm to drive positive changes and enhance community services at JCF.



Photo Coming Soon of Colleen Choi

Colleen Choi, Chief Operating Officer

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